Towards the Modulation of Phospholipase A2 by Trypanosomatids Infection
Silva-Cardoso, L.1,5, Walshe, D.P.2, Genta, F.A.3,5, Fuly, A.L.4, Lehane, M.J.2,
Silva-Neto, M.A.C.1,5, Acosta-Serrano, A.2, Atella, G.C.1,5
1Instituto de Bioquímica Médica, UFRJ, Rio de Janeiro, Brazil.
2Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom.
3Fundação Oswaldo Cruz, Rio de Janeiro, Brazil.
4Universidade Federal Fluminense, Rio de Janeiro, Brazil.
5Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular.
INTRODUCTION: Trypanosomatid transmission by blood-sucking arthropods still
causes a huge damage on human populations worldwide. Salivary anti-haemostatic
factors are important to keep blood fluidity during feeding of hematophagous
arthropods. In Rhodnius prolixus, vector of the agent of Chagas Disease Trypanosoma
cruzi, it was shown that LPC found in saliva is able to inhibiting platelet aggregation,
and increases the production of nitric oxide, an important vasodilator. Phospholipase
A2 (PLA2) hydrolyzes phospholipids yielding lysophospholipids and fatty acids. These
enzymes display a range of important roles in mammals, including the generation of
lipid mediators. In insects, phospholipases are related to poison, digestion, immunity
and reproduction. OBJECTIVES: This project aims to study the phospholipase A2
present in the salivary glands, its action on bioactive lipids generation and the
modulation of that protein by trypanosomatids infectio. MATERIAL AND METHODS:
PLA2s gene expression was detected by Reverse Transcriptase-PCR (RT-PCR),
Western blotting analysis was used to detect PLA2 protein expression using
commercial antibodies and PLA2 activity was measured by using the fluorogenic
substrate 12-NBD-PC. RESULTS: We found seven different PLA2s in R. prolixus
genome. Transcription of group VIA and XIIA genes was detected in salivary glands.
And PLA2 activity was found in saliva and salivary gland epithelium. In another
hematophagous, Glossina morsitans (African trypanosomiasis vector), already have a
PLA2 XIIA gene identify. Phospholipase activity in saliva was detected and when G.
morsitans is infected with Trypanosoma brucei or T. congolense activity is inhibited. By
Western blotting and Real time RT-PCR is possible show that the PLA2 expression
level is downregulated in infected flies. CONCLUSION: These results support the data
that Trypanosoma infection modifies salivary protein composition in the vector,
including PLA2. That could leads to a LPC decrease, reducing the anti-haemostatic
potential and culminates in hampered feeding performance, which may enhance
parasites transmission.
Keywords: Saliva, Trypanosomatids, Bioactive lipids.
Supported by: CNPq, CAPES, FAPERJ and INCT- Entomologia Molecular.